In the prior art there are a wide variety of tools that provide blades in which the blade is either folding or retractable. Some of these tools furnish a saw blade which is enclosed into a handle when not in use and extends out of the handle in a manner similar to a pocket knife when the tool is to be used as a saw. Some tools provide that the blade can be opened to several different positions.
Other tools that are commercially available provide blades that retract within a handle such as is found in utility knives. In these tools the blade retracts into a hollow portion of the handle when not in use and extends out of the handle when it is to be used as a knife. All of these tools are very handy for the worker. However, a worker who has need of a saw and a knife must typically carry two separate tools in their tool pouch. Carrying both of these tools along with assorted screwdrivers, hammers and other tools requires considerable room in a tool pouch and room in the tool pouch is limited.
Thus, there is a need for a compact, durable tool which can provide a worker with a combination utility tool which includes both a saw blade and a knife blade and enables the worker to saw or cut with the same tool.
U.S. Pat. No. 6,363,614 is one attempt at solving this need in the prior art. A knife blade and a saw blade are contained within a common handle of a tool. The knife blade is a standard utility knife blade, commonly available anywhere, used in prior art retractable blade utility knives. The knife blade extends longitudinally from the end of the tool handle alike other utility knives. The saw blade also extends longitudinally from the end of the tool handle. However, the saw blade is a custom blade that is not commonly obtainable anywhere. More importantly, the use of this tool requires the use of two hands. While the tool is held in one hand a lock and unlock cap 28 at one end of the tool must be turned counter-clockwise with the other hand to loosen blade 10 in order to either move the saw blade to an extended operable position or to retract it inside the tool handle. At either extreme the lock and unlock cap 28 must be turned clockwise with the other hand to lock the saw blade in that position.
U.S. Pat. No. 4,890,387 teaches a single tool having both a knife blade and a saw blade. The knife blade is a convention utility knife blade that extends longitudinally from one end of an elongated tool handle by manually sliding an actuator button on the side of the tool. This is a one hand operation. However, the use of the saw blade is a two hand operation. While the tool is being held in one hand a second hand must be used to pull the saw blade from within a slot in the side of the tool handle alike a folding pocket knife. The saw blade pivots out of the slot to be aligned with the elongated tool handle. There is no provision for replacing the saw blade.
U.S. Pat. No. 6,467,173 teaches a combination retractable saw and knife tool that is alike that taught in U.S. Pat. No. 6,363,614 and requires a two hand operation. While the tool is held in one hand a lock and unlock cap 28 at one end of the tool must be turned counter-clockwise with the other hand to loosen blade 10 in order to either move the saw blade to an extended operable position or to retract it inside the tool handle. At either extreme the lock and unlock cap 28 must be turned clockwise by the other hand to lock the saw blade in that position.
U.S. Pat. No. 5,023,996 teaches a combination retractable saw and knife device. This device also requires a two hand operation. There is a two part handle each comprising a saw blade housing and the two housings are pivotably connected at one end. A saw blade is mounted inside each housing and the blades are extended from the end of each housing/handle. Hacksaw blade 28 is deployed for use from inside its handle housing 48 by turning a knob 29 counter-clockwise to free the blade and extend it from its handle housing. Knob 29 is then used to lock blade 28 in its extended position. This two handed operation is repeated to retract hacksaw blade 28 inside its handle housing and lock it therein. A wood saw blade 31 is mounted inside the other handle housing 58 using a pair of spring loaded displaceable slides 34 and 35 having catches 36 and 37. The catches are received in notches 42 and 43 or 40 and 41 depending on whether blade 31 is extended from its handle housing or is retracted therein. Both of these blades require two hands to operate. For the hacksaw blade 28 the handle must be held with one hand while the other hand is use to turn knob 29, extract blade 28 and retighten knob 29. For the wood saw blade 31 the handle must be held with one hand while the other hand is used to squeeze catches 36 and 37 to release them from notches 42 and 43 and then to pull wood saw blade 31 from the handle.
A person who is working with or installing drywall/wallboard or other materials very often needs one hand to steady a piece of material to be cut while their other hand is used to cut the material. Therefore, a tool that requires two hands to operate is not practical. Thus, there is a continuing need for a new and improved combination drywall utility tool with knife and saw blades which addresses the unique problems associated with cutting and shaping drywall to be fastened to a support wall. More particularly, there is a need for a combination drywall knife and saw utility tool that can be actuated and used by a person using only one hand. The knife blade or saw blade can be easily extended, used, unlocked and retracted all using one hand. This leaves the person's other hand free to hold, steady and manipulate a piece of drywall while it is being cut.
Along and through one side of a prior art utility knife is a slot through which protrudes, and along which travels an actuator button. A person holding and using a prior art utility knife typically uses their thumb to first depress the actuator button and then move it along the slot through the side of the tool to expose the knife blade. When the actuator button is released the exposed knife blade is supposed to remain in its exposed position. However, too often during use the actuator button is inadvertently pressed and the knife blade retracts when the operator does not want it to. In addition, the actuator buttons have an integral spring that too often gets weak with use and being clogged up with material after continued use of the knife. When this happens the actuator button does not adequately perform its function of locking a knife blade in its extended position. Thus, there is also a need in art for a way to assure that an extended knife blade will remain locked in an extended position and will not inadvertently retract while in use.